Why is this a blunder?

Hi

I'm very new to chess. I don't really understand the analysis yet, but this makes no sense? if I put the king in check with the knight, I would of lost it? My actual move makes more sense?

Can anyone help me understand this, but Also how to use the analysis tools properly?

Thanks

You would have won the queen on a5. 

So, Nd5 check, black captures the knight, then you play Qxa5 winning the queen. 

I feel stupid now. Thank you.

Discovered attack and check at the same time is a lethal combo. The only thing that beats it is en passant checkmate 😃

Thanks guys. Yep, I understand now. I can't think that many steps in front at the moment.

It just takes time, experience and practice

Yes, the discovered check to win the Black Queen is a strong tactic. I will say that your "blunder" isn't that bad though. As the engine eval shows, Rae1 gives White the advantage by about +2.53 and this means that in this game position, White is still much better. 

Computers don't look at everything identical to how human players do. Since a computer can't "think" in positional motifs and patterns, then it is forced to calculate a ton and assign engine evaluations to every decision it comes across. This move you played was considered a "blunder" because it was however many centipawns (units chess engines usually use to measure evaluations) "worse" than the "best move" the engine calculated in the position. 

It is worth noting this because your "blunder" might be winning and in some cases - even the most simple. Yes, the discovered check is instantly crushing, but if you missed it then that doesn't mean the game was necessarily "blundered away"

Thanks for the replies. I never realised how deep the game was. Being totally new, I am only seeing the obvious at the moment, but am starting to gradually look at the bigger picture. I did win the game, but want to improve

Discovered attack on the undefended queen. I probably wouldn't have seen it either. This also shows why knights are so dangerous. It's the piece most likely to be able to pull something like this.

So, you haven’t weakened your position, you’ve missed an opportunity to hugely improve it.

Have a look here:

https://www.chess.com/article/view/the-discovered-check-reloaded

there are wonderful lessons on chess.com to learn all the main basic taktikal situations.

But then again, it's easier for other players to see the relevant moves from a given position than the actual player facing that position itself.

I'm pretty certain it would be more difficult for me to spot this move if I had started out looking from the very first move in the game.

+2.53 for Rae1 is still good considering that White's development is superior to Black's development.

Excellent explication !

In reality it was more a "missed gain" than a blunder that loose the game or material (Stockfish definition of blunder).  Often Stockish is confusing between blunders, missed gain etc...

Can you please share the link?

lol idk this is funny though

You lost your knight but they lost their queen

oh yea knight check wins u a queen